Punches for notching blanks and tubing



Oct. 9, 1956 w. M. BAKULA 2,765,348

PUNCHES FOR NOTCHING BLANKS AND TUBING Filed Sept. 12, 1955 2 Sheets-Sheet 1 INVENTOR. WaHer M. Bakula ATTORNEY Oct. 9, 1956 w. M. BAKULA 2,765,343

PUNCHES FOR NOTCHING BLANKS AND TUBING Filed Sept. 12, 1955 2 Sheets-Sheet 2 INVENTOR; Walter M. Bakula ATTORNEY PUNCI'ES FOR NQTCHlNG BLS AND TUBING Walter M. Baknla, Denver, Colo.

Application September 12, 1955, Serial No. 533,533

Claims. (Cl. 164-50) This invention relates to a device for notching the extremities of metal tubes so that they may be fitted to the sides of other tubes, and has for its principal object the provision of an exceedingly accurate, highly efficient tube notching device which can be placed in a punch press or actuated in any other desired way, such as by means of hydraulic jacks or levers to accurately form arcuate notches of any desired radius in the extremity of a metal tube.

Another object of the invention is to so construct the device that the notches will be be sheared outwardly from the interior of the metal tube so that all flattening and distorting of the tube is avoided.

A further object is to so construct the device that it can be quickly and easily adapted to accommodate tubing of various diameters and to form notches of various radii and so that it may be used for forming arcuate notches in the extremities of both round and square tubes as well as in fiat sheet metal strips if desired.

Other objects and advantages reside in the detail construction of the invention, which is designed for simplicity, economy, and etficiency. These will become more apparent from the following description.

In the following detailed description of the invention, reference is had to the accompanying drawing which forms a part hereof. Like numerals refer to like parts in all views of the drawing and throughout the description.

In the drawing:

Fig. 1 is a side view of the improved tubing notching device;

Fig. 2 is a plan view thereof;

Fig. 3 is an enlarged, fragmentary, longitudinal section through the throat of the improved tube notching device, illustrating the action thereof when shearing a piece of tubing;

Fig. 4 is a detail view illustrating the type of notch the device will form in a tube extremity;

Fig. 5 is a longitudinal section, taken on the line 4-4, Fig. 2;

Fig. 6 is a rear view of the tube notching device;

Fig. 7 is a detail side view of a punch block employed in the improved tube notching device illustrating a notch depth attachment applied thereto; and

Fig. 8 is a perspective view of the improved tube notching device.

The invention comprises an elongated, rectangular base block 10. Two upstanding bracket plates 11 and 12 are secured to opposite sides of the rear extremity of the base block 10 in any desired manner such as by means of suitable cap screws 13. A vertical guide block 14 is mounted between the two bracket plates 11 and 12, such as by means of cap screws 15. The guide block 14 extends from a position in alignment with the top of the bracket plates 11 and 12 to a termination in spaced relation to and above the base block 10 to leave an open throat 16 between the guide block 14 and the base block 10.

The guide block 14 is inset rearwardly from, and in parallel relation to, the forward edges of the two bracket plates 11 and 12 so as to form a vertical slideway 17 between the bracket plates for a crosshead 18. The crosshead 18 is maintained in the slideway 17 by means of two vertical track bars 19 and 20 which are secured to the forward edges of the bracket plates 11 and 12 and extend inwardly therefrom in vertical, spaced-apart relation. The track bars 19 and 20 are secured to the bracket plates 11 and 12 by means of suitable cap screws 21.

The crosshead 18 is accurately and slidably fitted between the two bracket plates 11 and 12 and between the face of the guide block 14 and the track bars 19 and 26.

The crosshead 18 is provided with a projecting portion 22 which extends forwardly between and in slidable engagement with the two track bars 19 and 20. A vertical punch member 23 is secured on the forward face of the forwardly projecting portion 22 of the crosshead 18 by means of suitable cap screws 24. The guide block 14 is formed with a vertical channel 25 in its forward face to provide clearance for the heads of the cap screws 24 as the crosshead is moved vertically.

The vertical punch member 23 is formed at its upper and lower extremities with arcuate, sharpened, hardened shearing edges 29 lying in horizontal planes. The forward face of the punch member 23, indicated at 30, is set back and flattened intermediate the shearing edges so that the arcuate shearing edges 29 will project forwardly from theforward face 30.

The crosshead 18 is resiliently supported on the upper forward extremities of a pair of U-shaped leaf springs 26. The lower forward extremities of the springs 26 are clamped fixedly in place beneath a clamp plate 27 secured to the base block 10 by means of a suitable clamp screw 28. The upward movement of the forward extremities of the leaf springs 26 can be limited and regulated by means of a stop plate 42 secured to the rear of the guide block 14 by means of a suitable clamp screw 43. The clamp screw 43 is threaded into the guide block 14 and passes through a vertically slotted opening 46 in the stop plate 42 so that the vertical position of the stop plate 42 can be adjusted to regulate the upward movement of the forward extremities of the springs 26.

An interchangeable die block 31 is positioned on the base block 10 immediately below the punch member 23. The die block 31 is of rather intricate design. It is of general rectangular shape having four sides and a flat bottom and top. The top is milled to provide a first semi-cylindrical cross channel 32 of a given radius extending across the middle of the block and a second semicylindrical cross channel 33 of a larger radius extending across the middle of the block at right angles to the channel 32. The four vertical sides of the die block 31 are arcuately grooved to provide four semi-cylindrical vertical channels 34 of differing radii.

The die block is clamped in place against the track bars 19 and 2% by means of a semi-resilient clamping key 35 which is urged against the die block by an eccentric cam extremity 36 formed on a clamping lever 37. The clamping key 35 is formed with a downwardly depending shoulder 41 which engages the side of the base block 10 and prevents the key from being moved during the rotation of the lever 37. The clamping lever 37 is hingedly mounted on a hinge pin 38 projecting upwardly from the base block 10 and is provided with a knurled handle 39.

The shearing edges 29 on each punch member differ in radius so that two punch members supply four shearing edges of differing radii corresponding to the four differing radii of the vertical channels 34 in one of the die blocks 31.

Let us assume that a punch member 23, with its crosshead 18, is dropped into the slideway 17 with a shearing edge of selected radius facing downwardly. A die block Patented 0st. 9, 1956 in which one of the cross channels 32 or 33 for instance the channel 32, corresponds to the outer diameter of the tube to be notched and in which the latter channel terminates in a vertical side channel 34 corresponding in radius to the lower shearing edge of the punch member 23 is selected. The selected die block is placed on the base block It) with the desired vertical side channel 34 positioned in alignment with the lower shearing edge of the punch member. This can be accomplished by forcing the punch member downwardly and fitting the die block thereto. The clamping key 35 is now siippcd between the eccentric extremity 36 of the lever 37 and the die block and the lever is rotated in a clockwise direction so that the increasing diameter of the eccentric extremity will frictionally pry against the clamping key to lock the latter against the die block to secure the latter inplace as shown in Fig. 2. The stop plate 42 is now adjusted vertically so that the lower shearing edge of the punch member will align with the upper surface of the die block. This will position the latter cutting edge diametrically and horizontally across the channel 32.

A tube to be notched, indicated at 40, is now placed in the cross channel 32 and forced forwardly against the fiat forward face 30 of the punch member 23, with the lower shearing edge 2? projecting into and diametrically across the inner diameter of the tube 40. The crosshead and its attached punch member 23 are now forced downwardly. This causes the two sides of the arcuate shearing edge 29 to move downwardly along the coacting arcuate shearing edge in the die block so as to shear the two sides of the tube outwardly and downwardly until the shearing edge passes completely therethrough, as shown in Fig. 3, to form an arcuate notch in the lower semi-circumference of the tube, as indicated at B in Fig. 4. The tube 40 is then rotated 180 and again passed forwardly over the lower cutting edge of the punch, and a second similar arcuate cut is made opposite the first, as indicated at A in Fig. 4, to form a complete cross notch in the extremity of the tubing.

it can be seen that tubes of various diameters can be notched by selection of the proper die block and that notches of various radius can be made by the proper selection and positioning of the proper punch member 23.

The punch member 23 and its crosshead 18 can be forced downwardly in any desired manner by any suitable means. For instance, the base block can be mounted on the bed of a punch press and a punch die in the press can be arranged to force the punch member downwardly at each actuation of the press. The springs 26 will return the block one-half the diameter of the tube being notched after each actuation.

Should it be desired to notch square tubing instead of the round as above described, it is only necessary to invert the die block so as to place its flat bottom upward with the proper vertical channel 34 aligned with the proper punch member and with the stop plate adjusted to retain the lower shearing edge within the square tubing when the latter is forced against the forward face 30 of the punch member. Flat sheet metal or plates can be similarly notched by placing the flat bottom of the die block upward.

The punch member 23 is provided with a tapped hole 47 by means of which a spacing disc 44 may be attached to the front face 30 of the punch member by means of a suitable cap screw 45 as shown in Fig. 8. The spacing disc 44 spaces the extremity of the tube: forwardly so that a shallower notch than normal may be formed in the extremity of the tube is desired.

A resilient cushion 48 is positioned on the base block 10 to prevent damage to the plate and crosshead 18 should the latter be accidentally forced downwardly too far.

While a specific form of the improvement has been described and illustrated herein, it is desired to be understood that the same may be varied within the scope of the appended claims, without departing from the spirit of the invention.

Having thus described the invention, what is claimed and desired secured by Letters Patent is:

l. A device for notching the ends of a tube comprising: a base block; crosshead guide means secured to and arising from said base block; a crosshead member slidably mounted in said guide means for vertical movement therein; resilient means supporting said crosshead member in said guide means; a punch block secured to said crosshead member; an arcuate cutting edge extending forwardly from the front face of said punch block and adapted to enter the open extremity of a tube; a die block resting on said base block, said die block having a vertical arcuate notch in one of its sides adapted to receive the arcuate cutting edge of said punch block when the latter is forced downwardly; an arcuate groove extending across the top or" said die block and intersecting said notch so that the tube may be rested in said groove with its open extremity about the arcuate cutting edge of the punch block and over said notch so that said cutting edge will cooperate with said notch to shear an arcuate base from the lower portion of the extremity of said tube; means for urging said die block forwardly toward said guide means; and means for stopping the forward movement of said die block when said notch is in position to receive said arcuate cutting edge.

2. A device for notching the ends of a tube as described in claim 1- in which the means for urging the die block forwardly against said stop means comprises a hinge pin projecting upwardly from said base block; aclamping lever hingedly mounted on said pin; an eccentric extremity formed on said lever about said pin; and a clamp bar positioned between said extremity and said die block'so that when said lever is swung about the axis of saidpin said extremity will force said clamp bar against said die block to urge the latter forwardly against said stop means.

3. A device for notching the ends of a tube comprising: a vertically movable punch block; an arcuate cutting edge extending forwardly from the lower edge of the front face of said punch block and adapted to enter the open extremity of said tube; a die block having a vertical arcuate notch in one of its sides said notch being adapted to receive the arcuate cutting edge of said punch block; and a horizontal arcuate groove extending across the top of said die block in which the tube is rested with its open ex-. tremity about the cutting edge of the punch block so that when said punch block is forced downwardly, said cutting edge will cooperate with the notch in said die block to shear an arcuate piece from the lower portion of the extremity of said tube, said punch block having two-ar cuate cutting edges of different radii one at each extrem ity thereof so that said punch block may be reversed to change the radii of the produced arcuate piece.

4. A device for notching the ends of a tube as described in claim 3 in which the die block is substantially rectangular and is provided with a punch receiving notch in each of its four sides, said receiving notches differing in radii so that said block may be rotated to place a notch of any desired radius in cutting position.

5. A device for notching the ends of a tube as described in claim 4 in which said die block is provided with two rectangularly intersecting tube receiving grooves in its upper face.

References Cited in the file of this patent UNITED STATES PATENTS Diekmann Oct. 17, 1950 

